1. Field of the Invention
The present invention relates to a cooking apparatus for food, such as pizza. More particularly, the invention relates to an open-air cooking apparatus, having a heated rotating turntable surface for conduction heating from below and a radiant heat source for cooking from above.
2. Description of the Prior Art
Existing commercial pizza ovens are typically of the deck type, based on an enclosed static surface. A deck oven can make a good quality pizza, but the temperature is not easily controlled or changed, and the operator must manually move the pizzas about within the oven to make room for additional pizzas, and to achieve an evenly cooked pie. Other types of ovens for large-scale baking include a conveyor type oven, also enclosed. These ovens rely primarily on convection heating, as well as a degree of conduction heating from below. The drawback of these systems, particularly with respect to the cooking of pizza, is that it is difficult to control a temperature gradient within the oven, either spacially or temporally. As pizza requires a longer cooking time for the base or crust portion, compared to the upper topping layer, the result is often a pizza which is overcooked on top, or vice versa. Furthermore, the marketing of fresh-baked pizza suffers a disadvantage based on the hidden nature of the cooking process. The consumer only sees the end product, but can not see the pizza as it is being cooked. With a closed, convection type oven, this is difficult to achieve. Even if glass windows are provided, heat loss is experienced, and the view is limited and static, particularly if several pizzas are being cooked at once. These traditional ovens additionally suffer from a drawback in that they take a very long time, usually several hours, to reach the desired cooking temperature.
U.S. Pat. Nos. 4,305,329 and 4,411,920 to Fenoglio teach a gas-fired turntable oven for baking several pizzas at once. A closed cooking chamber is heated by gas-fired burners located beneath the rotating turntable. The chamber is heated, and the pizza is cooked, by convection. In addition, a radiant heating element 23 may be provided above the rotating pizza. This reference does not teach an open-air oven, and does not teach a turntable constructed as a chamber containing vaporizable fluid, which turntable provides a source of even, constant heat for cooking by way of conduction.
U.S. Pat. Nos. 6,125,740 and 6,354,194 to Hedrington et al teach an open-air apparatus for cooking a single pizza. Radiant heating elements are provided both above and below the rotating turntable, which turntable is simply a support surface for the pizza. The upper and lower radiant heating elements are pie-shaped (i.e. in the form of a pizza slice), so that heat can be evenly applied to a rotating round pizza. In other words, the heating surface increases in width from the center of the pizza toward the crust portion. This reference does not teach a rotating turntable for cooking several whole round pizzas at once, which turntable is constructed as a chamber containing vaporizable fluid for providing a source of even, constant heat for cooking by way of conduction. Nor does this reference teach a source for heating the turntable from beneath, as the turntable is constructed to allow the radiant heat to pass through to the pizza located on top of the turntable.
U.S. Pat. Nos. 6,250,210 and 6,146,677 to Moreth teach a closed oven housing for cooking several pizzas at once on a rotatable turntable. Cooking is achieved by a combination of convection heat, conduction heat and radiant heat. A heat source is in thermal communication with the bottom of the turntable, and increases in intensity from the center towards the outside perimeter to account for the increasing panel area. This acts to heat the turntable itself, which is constructed of heat retaining material, preferably of ceramic, and transmits heat by conduction to the pizza. In addition, heat flows up and around the edges of the turntable to provide convection heating to the interior of the cooking chamber. A radiant heat source applies intense heat downwardly onto the top surface of the pizza at a focused area.
While Moreth teaches a turntable in the form of a thermal reservoir, heated from below, and a radiant heating element above, relies additionally on the availability of convection heating, and therefore requires a closed cooking housing or chamber. The heat for convection flows from the heat source below the turntable, around a space provided between the outer edge of the turntable and the inside wall of the housing. In addition, Moreth teaches that the heating element below the turntable runs essentially the length of the radius of the turntable and has increasing intensity from the center point outwards; and that the turntable is solid ceramic.
It is therefore an object of the present invention to provide an apparatus for cooking pizza, or other foods which require differing cooking times and/or different cooking methods for the top and bottom portions.
It is a further object to provide an open-air cooking apparatus which provides a full view of the food product being cooked, from the beginning to the end of the cooking process, for several items simultaneously.
It is a still further object of the invention to provide a cooking apparatus relying solely on conduction and radiation heat, without the necessity for convection heating.
It is an additional object of the invention to provide a cooking apparatus having a rotatable turntable as a conduction heating element, which element may be evenly heated throughout by applying heat to any portion.